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Darwinism: Six Scientific Alternatives
PETE A.Y. GUNTER

UniversityNorthTexas of

Introduction
Non-Darwinian common to evolution are today. approaches increasingly A significant number of capable biologists are pursuing research that points away from the classical idea that evolution consists only of chance point mu tations and natural selection. Other factors are arising, factors that compli cate this originally clear-cut picture. Current orthodox Darwinians would do well to reflecton a more recent historically grounded philosophy of science. the pronouncements of scientists, it could also make ness in the actual course of science.

make for would undoubtedly greater modesty in Although suchgrounding
for increased fruitful I would like to stress this last point. As this article appears in the first issue of The Pluralist, it seems fitting tomake a special plea for the recogni tion of the importance of plurality. The very title of this article proclaims the existence within scientific biology of a very real diversity.This might be ex as a very bad thing, since it suggests that evolution might be regarded various kinds of causes, and thus it risks losing its apparent plained through unilinear

overamplified) words of JohnStuart Mill, as amplified(and sometimes by
his twentieth-century disciple Paul Feyerabend: "John StuartMill, in his im portant essay On Liberty, went still further.He advised researchers not only

at such a juncture we might do well simplicity. But

to heed the

to retain ideas that had been tested and found wanting, but to consider new and untested conceptions as well" (33). Feyerabend goes further still, urging the "proliferation" of contrasting scientific theories. This approach would act as an antidote to credulousness (Preston, Munevar and Lamb grasp of subject matter.1 22) and may

to the other classical It is, among other things, assumptions of Darwinism. ultra-reductionist. Dawkins, Crick, Dennett, and their congeners seem not to know with Gnostic assurance that their theory is true; they seem only can never be or to know, beyond any doubt, that it seriously transformed

hold the view that while organisms do exist, they are es is exemplified toward reproducing genes. Ultra-Darwinism

we are in the entire future of biology (which, if replaced?not lucky,might on for thousands of Put in these terms-true now, undeniably true go years). forever?ultra-Darwinism turns out to have a strange kinship with Protestant non-fundamentalism. Though ultra-Darwinists become very upset when called "fundamentalists," an attitude of utter certainty begets utter certainty, and (aswith fundamentalism) alternatives are at best not plausible. At worst, fundamentalists are headed for hell; for ultra-Darwinists, lent end would be an epistemological Gehenna. the equiva

Biblical

epoch-making paradigm shiftmight, in the early years of the twenty-first century, stand in danger of being eclipsed. Yet this is a possibility thatmany contemporary physicists are considering. The defenders of ultra-Darwinism, by contrast, are sure that their "take" on evolution?their paradigm?can never, in any futurehistory of biology, be overturned or seriously transformed. The response to this prevailing attitude is to point not only to the history of science (including recent science), but also to the later twentieth-century philosophy of science. Post-positivistic philosophy of sciences is associated

It is interesting to note that the cover story of the September 2004 is sue of American is entitled "AfterEinstein." It is hard to conceive Scientific that the presiding genius of twentieth-century physics and the leader of an

with the Karl Popper, Thomas Kuhn, Imre Lakatos, Paul Feyerabend, and others. Kuhns terminology and many of his ideas have been taken over by

the newer philosophy of science has brought to bear on our un derstanding of the sciences is, precisely, history. From the vantage point of a history, the sciences do not pursue simple linear career, piling up truthwith remorseless accumulation. Rather, the sciences go through a series of zigzags, moving from one "paradigm" to the next in an unpredictable fashion, with What seriously aware of the Kuhnian historical approach, with its rise and fall of

scientists and the general public, and it is his viewpoint, with the notions of paradigm shift and revolutionary science, that I will use here.

is driven towonder what special epistemological status evolutionary biology has that insulates it from the conceptual shiftsobvious in the other natural sciences. Barring the demonstration of this special status, must not we admit that such transformation is at least possible? to the sciences, however, Having praised theKuhnian historical approach am now to criticize it. If the I compelled history of the sciences evidences not conceptual changes, it is clear that these do come in dramatic paradigm shifts. The move from Ptolemaic always simple, toNewtonian to physics, has Copernican astronomy, and fromAristotelian serious and fundamental

the possibility of any one paradigm one supposes, absolute prevailing forever.The absolute persistence (hence, of any one paradigm is not to be observed in astronomy, mathemat truth) central meaning ics, or physics. One

such unitary, dramatic contours. Significant changes in other sciences, how ever, have a different structure. arose in themid-i8oos and was codified at the Thermodynamics, which end of the century by Ludwig Boltzmann, remained essentially unchanged for decades. Then, was transformed?not by being beginning in the 1960s, it but by being broadened and deepened. Born of a system understood eclipsed in terms of linearity and equilibrium, thermodynamics came to be founded

on ideas of nonequilibrium. To be sure, the second law of thermodynamics has not been jettisoned. But its content will never be the same (Prigogine

and Stengers). A similar history attends quantum physics. Plancks constant (formulated

man, quantum physics is the work of many, and it has undergone several transmutations. We recall the reshaping of early quantum physics resulting (circa 1925-1927) in a now classical formulation. This significant reformula tion has been followed by others, some consisting of simple discoveries, others ofwhich embody real conceptual surprises.The most recent of these include Bell's theorem and quantum teleportation, decoherence theory, and the un expected emergence of the standard quantum into themacrocosm. into themezocosm, effects out of themicrocosm,

in 1900) stilllives. But unlike relativity work of one which is the physics,

I have been insisting on an alternative toKuhn sdramatic notions of para criticism can be lodged against Kuhn (and perhaps digm shifts.But another century. Newtonian overlap on physics

of Popper),again on thebasisof theactualhistory physicsin thetwentieth Though theseoften physicsplus quantum physicsplus thermodynamics.
important points, each is inconsistent with the others. Bluntly, a not not a three-ring circus. It is physics today is single, shining edifice but was a unified physics; physics today is relativity

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clear whether or how thisHumpty Dumpty can be put back together again. One hopes that the results of paradigm shifts or internal conceptual trans formations will lead to unified sciences, but that is doubtful (Horgan 322). There have been many efforts to falsify Darwinism, diverse efforts spring

with Marxism, religious fundamentalism, ing from assumptions associated to see that, over the past even is vitalism, and simple skepticism. It important has shifted few decades, the nature of such attempts to refuteDarwinism radically?has, by mere

critics argue that new discoveries in physics and chemistry, today and chemistry provide possible nonmechanistic, non-atomistic ex physics Far from saying that physics and chemistry cannot explain planations of life. the living organism, theywant to hold that ultra-Darwinism either fails to continue its reductionism all the way (e.g., to quantum reality) or fails to consider alternative reductions (e.g., roughly, to nonlinear phenomena).

The notion of particles as tiny bits of billiard-ball-like matter that get to themselves is a hard one to pushed and pulled about by fields external to rest. The relatively recent experimental confirmations by French put

of Einstein and his colleagues physicistAlain Aspect of the predictions has finally forced the realization thatmechanical interpretations of ba sic physical processes have to be abandoned and replaced by a much more view of the dynamics of change at the integrated, interconnected fundamental level of physical reality. (173)

Goodwin

amounts to a goes on to speculate that the new purview of physics in the nature of physics and biology, and to their interrelations: change more physical and mathematical, putting the Biology thus becomes of genetic, developmental and evolutionary studies intomore insights at the same time, physics becomes more bio precise dynamical terms; more evolutionary, with descriptions of the emergence of the logical, four fundamental forces during the earliest stages of the cosmic Big of the elements Bang, the growth sequences of stars, and the formation during stellar evolution. (71)

In his depictions of the new relative status of physics and biology, Good win goes further thanmost contemporary scientists.The Newtonian orNew tonian-like ideas that have dominated modern science, as Goodwin sees them, die hard. He projects not somuch the present state of the sciences as a future state, perhaps not so far over the horizon.

Gunter

:Darwinism

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The SixAlternatives
For the sake of argument, Iwill sketch six current, scientifically based alterna tives toDarwinism: quantum evolution; thermodynamic evolution; "chaotic" or nonlinear evolution; neo-Lamarckian evolution; Baldwinian evolution; hypothesis. first of these (quantum evolution) will take the pole position, pri a will special hearing. No effort marily because it is less known and deserves be made to provide an in-depth explanation of each view, though every effort The will be made to a concerted effort Though thewriter has made these contrasting views, he makes no claim to complete bring together ness. There may be others. to be accurate. Evolution and Margulis s genome-capture

Quantum

A theory that attempts to derive the emergence and evolution of life from fundamental quantum phenomena is found in Johnjoe McFaddens Quantum Evolution (338). Two new factors in quantum physics support McFaddens mezocosm and the theory: the discovery of quantum effects in the develop ment of decoherence decoherence is a recent permutation of Quantum theory. the basic approach to quantum measurement. For the purposes of a quantum most important of which biology, decoherence has several advantages, the is its denial that a human observer is needed for a successful observation.

Decoherence

mezocosm

It is less a theory is unconnected with quantum decoherence. an than experimental achievement. It has been assumed that thewell-known quantum effects (wave-particle duality, Heisenberg s relations, tunneling) ex ist only at the level of one or a few subatomic entities. (I refuse to call them even so an object weighty particles.) Recent experiments, however, show that as buckminster fullerine can, under the right conditions, exhibit "quan (C60) tumweirdness." Even a very hefty "buckeyball" behaves ? laHeisenberg (C70) and shows wave-particle duality.

theory is thus epistemologically realist. It denies, among other wave function. things, the observer-induced collapse of the The recent emergence of quantum effects from themicrocosm into the

new mezo particular approach). First, the yond the confines ofMcFaddens to rest the notion that must scopic quantum effects surely put Heisenbergs

be followfromthis, Two things both of verygeneralimport(reaching

on uncertainty relations are caused by the impact of the measuring device the object measured. Photons, protons, and electrons cannot have a sufficient or to cause uncertainty in position or momentum. Second, effect on C60 Cyo

8 though most

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6

believe that the peculiar biologists (and neurophysiologists) effectshave nothing to do with brains, organisms, or evolution, this quantum

and is thepoint of McFaddens book. maywell have tobe revised, opinion

some replicator is surprisingly specific. He proposes that the emergence of that can replicate itself and thus initiate the beginnings of lifemust thing have occurred in a relatively protected area (a "protocell"), which could be as

on McFaddens attempted restructuring of biology is twofold, touching the emergence of life from nonliving matter (presently an unresolved prob lem) and the subsequent evolution of life.His concept of the first chemical

wait 3.5 billion years for a human observer in order for decoherence to occur. Decoherence would occur when the peptide is, as would happen sooner or later, affected by its environment. The resultwould be the emergence of the out of the quantum state, intowhich state it could peptide again drift pend contact and decoherence: and so on, ing another environment indefinitely. This cycle would have continued as the peptide added more and more amino acids. Some amino acid additions?those that did not counter en

as a cavity in a rock. The candidate he offers for this first simple replicator is a short peptide chain, which can function as an enzyme. A short peptide, along with others of itskind in a protected cell, need not

have taken place in the quantum realm, whereas zymatic activity?would others would have precipitated quantum measurement and a brief return to theworld of classical physics. This process would have continued to elongate the quantum collapsed would have taken place is easy to predict: it would have been when to tide learned self-replicate (McFadden 227).

superposition of possible peptides until the system irreversibly into a classical state. The point at which this irreversible collapse the pep

Thus, McFadden urges, there is a previously unsuspected capacity at the limits of quantum reality for quantum phenomena to produce biologi upper cal order, including the dynamic sort of order exhibited in replication. McFaddens model 32-amino-acid replicator, he reasons, would have to

a test (natural selection), a more continuing Darwinian undergo producing "fit" replicator, through, among other things, the captive of "lipid membranes, or nucleic acids" (236). The result?one a considerable peptides, requiring stretch of time?would

be the first, simplest cell. account of the I will not attempt to present McFaddens development of cells and multicellular organisms, the grand sweep of biological evolution to "measure" their own quantum states involving the ability of living cells and respond with increasing sorts of complexity. Iwould, however, like to put forward two speculations here before pro

Gunter ceeding

:Darwinism to the thermodynamics

19

dismisses theory of evolution. McFadden (nonlinear) thermodynamics as having anything important to contemporary do with evolution. His own quantum explanations provide, he says, a negen tropic vector for life's history of increasing complexity. But compared with the linear thermodynamics of Clausius and Boltzmann, forwhom natural processes can produce either relative disorder or static form ("crystalliza tion"), nonlinear thermodynamics is negentropic:

it creates new levels of

of and dynamicform(hence, higherlevels complexity) could (andprobably
is, for example, to keep the should) play a role in biological evolution. What new (mezoscopic) nonlinear processes studied in the thermodynamics from quantum effects? to quantum evolution in The

Worm (282). Though rich in conceptual content and diverse Rainbow and the in subject matter, Ho's biology, in fact, rests on a few basic claims. In three respects, she argues, the living organism differs from our ordinary understand ing of it: (1) its thermodynamics differ fundamentally from both the linear more recent nonlinear thermodynamics of Boltzmann and the thermodynam

a state that most fun crystal, chemical easily accepts re-alignment; and (3) its damental causality is not that of DNA, RNA, or the familiar electrical and chemical process that govern nerve function. Rather, it isquantum coherence Ho's that directs the organism's activities. It is tempting (if inelegant) to describe as a stool that sits on three theory legs.This image ismisleading, how

icsof IlyaPrigogine his colleagues;(2) itschemistry that the liquid and is of

ever, since it suggests three independent theoretical parts, while (consistent with her organist viewpoint) her three primary components are profoundly interwoven. Each requires, and is closely involved with, the other.

percent efficient,while other biochemical processes rival this rate. The re sult is that the organism produces surprisingly little entropy and is thus able to store energy and to act without s easily using it up. Ho understanding of

The author's thermodynamics reston some remarkable (but littlenoticed) facts. In living organisms the efficiency of essential chemical processes reaches remarkable levels: photosynthesis and muscle contraction are one hundred

entropy ismore subtle than these words suggest. Both linear Boltzmannian and nonlinear Prigoginean entropy are necessary conditions of Ho's "third " thermodynamics. The term liquid crystal may sound unfamiliar, even self-contradictory. In fact, liquid crystals are common in nature. The kinds of rigid crystalswe are used to (salt one limit of a crystals, quartz crystals) constitute only crystal are are continuum. At the other end which disordered. In liquids, relatively

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to electric and changes in orientation and/or phase transitions when exposed fields. magnetic

All major components of living organisms may be liquid crystalline: in chromosomes, cytoskeletal proteins, lipids of cellular membranes, DNA muscle proteins, collagens, and others. Liquid crystals typically undergo rapid

between are the liquid crystals,which have some characteristics of crystal lat tices and some of ordinary liquids. Being a liquid crystal is a matter of degree: "Unlike liquids which have little or no molecular order, liquid crystals have some common an orientational order, in that the molecules are aligned in rather like a crystal. But unlike solid crystals, liquid crystals are direction(s), flexible, malleable, and responsive" (Ho, Rainbow 173).

stores of energy that science has not un fully Living organisms possess derstood or taken account of; in addition, they are neither solid (aswe usually conceive of their skeletal material) nor liquid. They are "solid states," held

together both within the cell and between cells by omnipresent connective tissues,which make very rapid?unexpectedly rapid?signaling possible from to part, part towhole, and whole to part. part naling? Ho is to create, and, where necessary, to direct this ceaseless sig does not deny that brains, nervous systems, and other standard systems exist and play important roles. She believes that communicating But what

quantum physics, however, introduces an all-important factor that has not been recognized: quantum coherence. We have discussed this new approach to quantum

quantum biology, noting phenomena in reviewing McFaddens both that it removes the necessity of the human observer from physics (and

from thermodynamic equilibrium and is coherent simultaneously in awhole range of frequencies that are nonetheless coupled together" {Rainbow 152). That is, the different components of the organism, each with theirown tempos are made a synchronous by quantum-coherent field. (biological rhythms), A coherent system exhibits neither space nor time separation. A change to the others, in one part is "instantaneously" communicated regardless of

out of themicrocosm into themezocosm. Ho biology) and is slowlymoving takes advantage of both these factors: "The living system is one coherent to matter. This "photon field" bound living photon field ismaintained far

the distance between them. Yet, paradoxically, coherence can be compared or her own to a "large jazz band, where everyone isdoing his thing, yet keep coherent system thewhole does not ablate the parts; nor can thewhole reduced, atomistically, to the parts.

in with the whole" {Rainbow 210).Thus, in a ingperfectly timeor in step
be

Gunter

:Darwinism

21

matter. Itwould

Ho writes with remarkable brevity, considering the range of her subject be worthwhile to consider, for example, theways inwhich coherent fields may coordinate both the organisms movements quantum to and its Bergsonian multiplicity of biological rhythms,which she compares duration {Rainbow 242). Itwould also be helpful to examine the evidence for information transfers in the organism that are faster than the nervous

the views of system can account for (Ho, "Quantum" 265-76). Comparing in synch, sometimes not) would also illu Ho and McFadden (sometimes minate the debate. to gives rise many questions, Examining thework ofHo and McFadden which criticswill be sure to stress. It is impossible to avoid a significant conclu

sion, however. Only now is itpossible for quantum physics to begin to help us understand the living organism. The results inevitably will change many fundamental concepts: in genetics, in neurophysiology, and in evolutionary are to be radical. likely theory. Some of these changes

Thermodynamic Evolution was to to hear him thermodynamics surprised biology, I nonequilibrium reiterate his belief that nonlinear autocatalytic chemical reactions could be to the genetic manipulate responsible for evolution through their capacity

In several of with IlyaPrigogine the discussions concerning relationship his

on almost all who attempt virtually negligible today. In fact, his influence to is profound?though scientific alternatives to ultra-Darwinism provide often not admitted. Dorion Sagan takes up the case for thermodynamic evolution in "Sym biosis Purpose, and Direction: Evolutions Roots in Energy Flow's Natural Designs": argue that computerized simulations, no less than intelligent or foundational of humanity itself,are not exemplary intelligence but a subset of naturally complex thermodynamic systems. These represent Iwould systems naturally cyclematter in complex ways and undergo spontane ous, elaborate path-building regimes in order to come to equilibrium. Please pay attention to this "in order"; such activities,which occur in

predetermined in its results. Prigogine's achievements, by their very nature, invite extension from chemistry to biology, the gap between the two being

code, producing new genetic information?not through chance mutation but not a a purposeful process in through spontaneous creation of dynamic form; the usual sense, because it is "experimental," vectored toward form but not

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real time, require no genetic machination. They are completely natural and their complexity... is a byproduct of the entropy-production func tion implicit in the second law.2 (Sagan 2) Once one considers the new possibilities opened by the thermodynamics, s views are seen as Sagan plausible?even inescapable. Evolution

Nonlinear

The physics of chaos or nonlinear dynamics is a field that, by nature, is broad to encompass quantum enough phenomena and thermodynamics. To distin not guish the physics of chaos from thermodynamics and quantum physics is tomake

a mistake per se, but the distinction needs to be qualified. All three involve nonlinearity and the emergence of form. But the physics of chaos has its own concepts and should be treated separately. The literature associated with this field is immense. For the sake of sim

I plicity(andbrevity),willmention only twobooks:BrianGoodwinsHow

theLeopard Changed Its Spots and Stuart Kauffmans At Home in theUniverse (321). Both these works have as a starting point not a specific physics but a awareness of sciences discovery of self-organization, spontaneous generalized order, order for free, and complexity. Kauffmans and Goodwin s books involve very different approaches

to

as can focusing "on the types of order that in complex systems and the role of natural selection as emerge spontaneously an external force that drives the system into particular stages of adaptation" (186). That is,most of the order we see in living nature is an expression of properties inherent in complex dynamic systems. Simple rules of interaction scribes Kauffmans achievement

their subject matter. Kauffmans quasi-experimental computer-oriented re search rarelydescends to the level of specific organisms, specific evolutionary bifurcations. Goodwin, on the other hand, pays special attention to specific in geometrical terms. Goodwin de organisms, exploring theirmorphology

between large numbers of elements create living order. It follows that natural selection is not all that significant in producing life forms. There is "order for free,"Kauffman insists, and it emerges spontaneously without having to on be chiseled out gradually by natural selection point mutations. working Goodwin happily proclaims that his work and Kauffmans, though they start from different considerations and with different orders of fact, converge to common remain. Does

true. But the (non-Darwinian) insights. This is problems still theGoodwin-Kauffman alliance reston quantum foundations, on or on both (which poses thermodynamic foundations, problems)? Or is seem that their "consensus" separate, free floating? If so, itwould physics

Gunter

:Darwinism

23

author suggests a rapprochement between the two. Perhaps some third ap proach is necessary. Two more possibilities open up at this point, potentially complicating and "Baldwinian ideas." the three sketched so far: neo-Lamarckianism Evolution

as the fourth a today is four-ring circus, with the physics of chaos ring (not a fifthwheel). A second stems from an unresolved tension in the problem on space, and neither two thinkers. Kauffman's focus is on time,Goodwins

Neo-Lamarckian

Lamarckianism, a live option around the turn of the last century (1890-1910), was to beat a retreat in continuing biology, being finally expelled from its last stronghold in unicellular organisms by Joshua Lederberg in the 1950s. Several factors have brought itback, as it were, limping from the dead. Some of these include Barbara McClintock of reverse transcriptase, with her defense of heretical Lamarckian discovery of the dynamic genome and views,3 and Howard Temin s discovery s

transmission, from protein to RNA. Similarly, though later disproved, John Cairns s 1988 experiments, interpreted as establishing guided mutations, have led to further research in the direction of Lamarckian mutations4 (Cairns, Overbought, Probing 142-45). the literature of recent Lamarckianism and Miller

RNA toDNA. Temin'swork opened thedoor to thepossibility further of

its transmission of protein "backward"

from

two interest provides The first is thatwhile Lamarck and many of his followers (e.g., ing insights. effort of the giraffe lengthening its Nietzsche) emphasized volition?the Lamarckians reject voluntarism, speaking of the useful neck?contemporary "stress" that the organism undergoes as the transformative factor.The second is that there appear to be two kinds of Lamarckian inheritance?one perma nent, the other "temporary." The existence of permanent, inherited, acquired

characteristics is hotly debated. Even so, some examples are hard to refute. Horny patches on the breast of the emu are embedded in both its skin and in its genes. Somehow this flightless bird has been able assimilate an environmentally induced structure.Meanwhile, genetically short term, "Lamarckian effects" arewell established. Water fleas, confronted to its breastplate?and

with predatory phantom midge larvae, grow huge helmets that serve to halve theirmorality rates.These helmets are then passed on to the second, and in a less to the third and fourth pronounced form, generations. Radishes, when

chewed on by cabbage butterfly caterpillars, produce 30 percent more spikes on their leaves, and ten times more repellent mustard oil glycosides in their are on to the second generation and, in diminished de leaves. These passed

THE PLURALIST gree, to the third generation. That question is how they occur.5 Whether Lamarckian

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such effects occur is unquestionable.

nition of "Lamarckian"

toDNA or not). A powerful marshalling of evidence in the former, broader sense ispresented by Eva Jablonka and Marion J.Lamb inEvolution inFour Dimensions, a comprehensive book on current trends in now-blossoming Lamarckian biology. from protein to RNA forLamarckianism The four "dimensions of evolution"

is hard to come by.Any genomic effect that appears in one generation other than by chance mutation and can be transmitted to the next is, strictly speaking, Lamarckian, since it involves the "heredity of acquired characteristics" (whether this involves transmission of information

or short run, the variety of effects that can be termed long ishard to corner in detail. In part, this is because the exact defi

the authors examine are genetic, as we will see, all four epigenetic, behavioral, and symbolic. And although, are not found in all sorts of all have the same effect: that living organisms, is, they account for inheritable effects (and thus in contrasting ways for the course of evolution) without recourse to chance mutations. The authors having (but, orthodoxy, does allow for the place of chance mutations not these). only interestingly, It is customary to conceive of variations in the phenotype as entirely a function of the genes, and that changes in the genes are entirely a function

claim indealing with thegenetic with which, in line dimension, modify this
Darwinian

Not

Jablonka and Lamb believe this approach is outmoded. does the "knocking out" of genes participating in important de only not affect the velopmental pathways often phenotype at all (63-64), many

of chance mutations.

than elsewhere. This activity is focused: that is, it is targeted for functions that involve much diversity (like the requirement of being able to avoid im mune-system responses). The authors explore what is known about all such processes, noting that at one extreme (the sheer random increase inmuta mutation

are a function of bacteria a hostile envi changes in the genes encountering ronment. Mutation rates in other bacteria contain stretches of DNA ("hot spots") whose mutation rate is hundreds, ifnot thousands, of times higher

nor their importance. It is surprising to learn, however, that blind mutations are not the source of genetic only variation. Increasingly, others are being found that are, simply, a function of the genes themselves. existence of classic "blind" mutations

tions of all sorts), such effectsare random, while at others (inwhich increased rates are limited to genes that influence very specific characteristics of the organism), effects are clearly targeted. The authors deny neither the

gunter The

:Darwinism second sort of variation

2-5

which

(and of inheritance) is "epigenetic": it is not created the genes at all, but by factors external to them. The authors by describe four EIS (epigenetic information systems), themost impressive of is termed the chromatin marking system. Chromatin is what chromo somes aremade of, and are consist ofDNA mol they spatially complex. They ecules wrapped around histones (small proteins), twisted tomake chromatin which is compacted tomake chromosomes. Thus DNA gets "packaged" fiber,

(think of ropes wrapped around ropes, twisted into loop-like assemblages). a stretch ofDNA is in the chromosome Exactly where "package" determines will be active. The decisive point here is that much about whether/when it features of chromatin can bepassed from one generation to the next. These heritable features are called "chromatin marks," which influence how can be turned on or off.The results are easily genes striking: which genes are and hence what features the adult organism will have, isnever expressed, a function of theDNA alone, but also of the chromatin marks, which may non-DNA be inherited generation after generation. The genes cannot, therefore, be as selfish as some would have them to be: they are constrained by chromosomal "social" factors surrounding them. Both genetic variation and epigenetic inheritance systems occur and func tion in unicellular organisms. It had long been assumed (prior to the 1980s) that inmulticellular organisms making sperm and ova, the epigenetic past is completely erased. This limitation has been overcome. The

among other evidence, the part played by chromatin marking not coat in toadflax and in heredity in laboratory mice. In the latter, only and color but obesity, diabetes, and susceptibility to cancer are passed along
via "epimutations."

genes are brought into action ("unmasked"). Natural selection in the new context will lead to the out of to it, thus organisms less suited dying "fixing" the newly used genes in the population: in thisway, behavior shapes the ef fective genome. Finally, the authors explore the symbolic inheritance system.This is the final step up "evolution mountain." The first step utilizes both Mendelian and non-Mendelian genetics. The second involves these as well as new epigenetic

thesis,which says that genes are surprisingly rich in alternative developmen tal pathways, many of which are "masked." Behavioral options pursued by the organism may lead to choices of new niches inwhich hitherto unused

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are to construct cultural niches and, hence, highly complex societies that not accessible apart from verbal skills. Like behavioral evolution, evolution use of occurs creates new situ through the linguistic symbolism, which then ations favoring some genes while minimizing others. The latterwill tend to become genetically fixed. Like behavioral evolution, evolution via symbolic communication falls under the general heading of Baldwinian evolution. Evolution

factors, and leads to the emergence ofmulticellular creatures. The third step involves behavioral alternatives that become fixed in the genes. The fourth step is limited to human beings, whose capacity to use language allows them

Baldwinian

The Baldwin Effect refers to the initiative taken by organisms tomove into a new, different environment, whose selective pressures may then mold the a new way. This is often understood in terms of organism in speciation. Al is speciation caused by geographical factors: mountain lopatric speciation ranges, rivers, deserts, all of which apart. Sympatric speciation?now same or areas. For the speciation occurring in the overlapping geographical former, lifeappears as passive in the hands of the environment. For the latter, separate populations, which then drift to be seriously studied?is beginning

were introduced into thewild only two centuries ago; genetic differ Apples ences between the two groups of flies are now being observed. are the Other candidates for sympatric speciation peppered moth, Megar

the organism selects a new environment, perhaps by changing what it feeds on hawthorn become hawthorn maggot Maggot flies that lay their eggs flies.Maggot flies that lay their eggs on apples become apple maggot flies. on.

There

hyssa wasps, pitcher plant mosquitoes, crickets, lacewings, and African para sitic finches (West-Eberhard 793). As with the Lamarckian option, themany Baldwinian approaches are embroiled in controversy.Their option, however, as would have been the case a few years ago. cannot simply be dismissed, are too many new explanatory phenomena. the horizon.6 New

schemes loom on

The Genome-Capture Hypothesis
It is no small problem to explain how the first nucleated (eukaryotic) cells arose. If we have Lynn Margulis is right, overcomplicated the problem. Instead of looking for chance mutations and their gradual accumulation via natural

selection, we should look at theway inwhich a host cell can appropriate the genome of a bacterium (prokaryote) and turn the newfound genetic arsenal to its own states: advantage. Margulis

gunter

:Darwinism

Any bacterium can pass genes to any other.Restrictions on promiscuous gene flow, and thus to the possibility of speciation, began in the lower Proterozoic eon, about 2,500 million years ago, when the transforma tion from bacteria cells to consortia and communities led to integra tion and boundary-making, and finally to the earliest Eukaryotic cells. These cells, as we have explained elsewhere, are themselves symbiotic as even assemblages. Eukaryotic cell parts such mitochondria and maybe microtubules originally evolved as free-livingorganisms. cilia and their {AcquiringGenomes 6$-66) technical term for the creation of new species Symbiogenesis?Margulis's the origin of the union of previously existing organisms?explains through a species in double way: through the bringing-together in the ancient past to form creatures

capable of speciation, and through the subsequent creation new of species by the incorporation of organisms and (eventually) of their genomes. Margulis provides copious examples of organisms "appropriating other organisms" in states of symbiosis. Equally impressive is the realization of how many organisms contain the genes of other organisms: some 250 of themore than 30,000 human genes, for example, come directly from bacteria {Acquiring Genomes y6).

worth,or (as inyeast)nearlyevery gene in thecells little body {Acquiring
Genomes 77). Hence, the of evolution and of the fossil record. ^continuity Evolution occurs not continuously but dramatically, through the capture of whole new genomes. This process is Lamarckian, but in a way unimagined or Steele. It involves the inheritance of byMcClintock acquired genomes. Conclusion Other options than the handful of un-Darwinian alternatives we've examined Various theories of "autopoesis," here could have been offered up to scrutiny. for example, might have been covered. These

Every organism that has been studied has some detectable degree of gene a part of an older gene, a set of a few genes, a chromosomes duplications:

within theconfines thephysics of and biologyof chaos, thoughit would be
to determine how the views of various chaos theorists interesting diverge, inwhat ways. and What then follows from all this? First, the abundance?an increasing scientific alternatives to Darwinism as

seem to me, however, to fall

strongly suggests that not immune to Darwinism presently constituted is change. Usually, those who talk about such a change talk in terms of dramatic Kuhnian shifts or abundance?of

28

THE PLURALIST

I : I 20 6

grand Popperian falsifications. But there are also significant permutations within a science, inwhich, though original terms remain (as in thermody namics and quantum physics), theirmeanings are significantly transformed. So it is, I believe, for ultra-Darwinism. Second, the sheer plurality of competing scientific alternatives poses a one side of this to accept problem. In taking only problem, itbecomes hard one of the as true once this any competing alternatives absolutely plurality is recognized. Other alternatives, sufficiently extended or developed, might do as well. Alternatives not yet formulated might come into the picture. This situation, itmight be argued, is (in spite of appearances) a good

run. It thing in the long justmight turn out that there are several valid ap to as there are to literature or or human culture. proaches biology, history Can science livewith a real diversity of approaches? One would hope so. In would any case, given that evolutionary theorymay become complicated, it be ill advised to exclude conceptual pluralism de jure, at the beginning. But perhaps pluralism is not at odds either with the existence of a great deal of unity in our knowledge or with the quest for unity. The idea of

among the arsenal of pragmatic tools. One could argue that the real goal of pluralism, with its diversity of viewpoints, is not disjunct disunity, but as the summation of the wholeness?wholeness diversity of approaches to theworld. If there is any notion that might bring some measure of cohesion to the emerging plurality of approaches in biology, it appears (to thiswriter, at least) to be nonlinearity. This idea is already common to quantum physics, thermodynamics, and the physics of chaos. I believe that it can make a con and Baldwinian approaches by establishing the active and dynamic character of both genes and organisms. Under the a still greater unification. aegis of quantum biology, it might bring about NOTES .For some of the problems of proliferation,see PeterAchinstein, "Proliferation:Is ita Good Thing?" (Preston, Munevar and Lamb 37-57). See also essaysbyElizabeth A. and PaulM. Churchland in the same volume. Lloyd 2. For a fulldevelopment of thisviewpoint, see Schneider and Sagan 345; Schneider
45-56.

is not possible here to enter into a detailed discussion of James's approach to urge, however, that it is no accident that he knowledge. I would like wrote about a pluralistic universe and attempted to find a place for unity to

with thephilosophy William James.It associated of pluralismisordinarily

tribution to various Lamarckian

Gunter

:Darwinism

29

but

McClintock's life and thought,seeKeller 235.For a brief 3?For an excellentaccount of
revealing account of her Lamarckian position, see McClintock 174-93.

of 4. For a brief rundown on the refutation Cairns thesisand the resultingresearch derived from it,seeTim Beardsley,"Evolution Evolving," Scientific American, Septem
ber 1997, research, 15-16; for a spirited defense of neo-Lamarckianism see Steele, 286. Lindley, and Blanden "Threatened" Milius, 151; "Tadpole" and an account of recent